RS-09-024, Request for Alternative to Nozzle-to-Vessel Weld and Inner Radius Examinations
ML090620369 | |
Person / Time | |
---|---|
Site: | Quad Cities ![]() |
Issue date: | 03/02/2009 |
From: | Simpson P Exelon Generation Co, Exelon Nuclear |
To: | Document Control Desk, Office of Nuclear Reactor Regulation |
References | |
RS-09-024 | |
Download: ML090620369 (10) | |
Text
Exelon Ni . ::ear Nuclear 10 CFR 50 .55a RS-09-024 March 2, 2009 U .S . Nuclear Regulatory Commission
- Document Control hington, DC 20555-0001 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating Licenses No . DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265
Subject:
Request for Alternative to Nozzle-to-Vessel Weld and Inner Radius Examinations In accordance with 10 CFR 50.55a, "Codes and standards, , paragraph (a)(3)(i), Exelon Generation Company, LLC (EGC), is requesting relief from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," (ASME Section XI).
Specifically, EGC requests NRC approval to implement an alternative from ASME Section XI, Table IWB-2500-1, "Examination Category B-D, Full Penetration Welded Nozzles in Vessels
- Inspection Program B," to allow reduced percentage requirements for Nozzle-to-Vessel Weld and Inner Radius Examinations at Quad Cities Nuclear Power Station (QCNPS), Unit 1 and Unit 2. This requested relief is consistent with ASME Code Case N-702, "Alternative Requirements for Boiling Water Reactor (BWR) Nozzle Inner Radius and Nozzle-to-Shell Welds." EGC is requesting this relief for the remainder of the fourth 10-year interval of the QCNPS Inservice Inspection Program, which began on March 10, 2003 .
The NRC has recently approved a similar request to adopt an alternative to ASME Section XI, Table IWB-2500-1 to allow reduced percentage requirements for Nozzle-to-Vessel Weld and Inner Radius Examinations for the Duane Arnold Energy Center. This approval is documented in ADAMS Accession Number MI-082040046.
The request is described in the attachment and enclosures to this letter . EGC requests approval of this request by March 3, 2010.
There are no regulatory commitments in this letter .
March 2, 2009 U . S . Nuclear Regulatory Comm Page 2 If there are any questions concerning this letter, please contact Mr. John L. Schrage at (630) 657-2821 .
Patrick R. Simpson Manager - Licensing Attachment : Quad Cities Nuclear Power Station, Unit 1 and Unit 2, Relief Request 14R-17 Enclosure 1 : Relief Request 14R-17, Applicable Nozzles Enclosure 2: Relief Request 14R-17, Plant Specific Applicability
Attachment Quad Cities Nuclear Power Station, Unit 1 and Unit 2 Relief Request 14R-17
Attachment Relief Request Number 14R-17 Proposed Alternative In Accordance with 10 CFR 50.55a(a)(3)(i)
Which Provides an Acceptable Level of Quality or Safety 1 .0 ASME Code Component(s) Affected Code Class:
Component Numbers: N2, N3, N5, N6, N7, and N8 Nozzles (See Enclosure 1 for complete list of nozzle identifications)
Examination Category: B-D Item Number: 83.90 and 83 .140
Description:
Alternative to ASME Section XI, Table IWB-2500-1 (inspection Program B) 2.0 Applicable Code Edition and Addenda Quad Cities Nuclear Power Station (QCNPS) is currently in the fourth 10-year Inservice Inspection (ISI) Program interval and is committed to American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," (ASME Section XI),
1995 Edition, 1996 Addenda. Additionally, for ultrasonic examinations, ASME Section XI, Appendix VIII, "Performance Demonstration for Ultrasonic Examination Systems," of the 1995 Edition is implemented, as required and modified by 10 CFR 50.55a(b)(2)(xv) .
3.0 Applicable Code Requirement Table IWB-2500-1 "Examination Category B-D, Full Penetration Welds of Nozzles in Vessels - Inspection Program B" Class 1 nozzle-to-vessel weld and nozzle inner radii examination requirements are delineated in Item Number B3 .90 "Nozzle-to-Vessel Welds" and 83.100 "Nozzle Inside Radius Section." The required method of examination is volumetric. All nozzles with full penetration welds to the vessel shell (or head) and integrally cast nozzles are examined each interval .
the All of nozzle assemblies identified in Enclosure 1 are full penetration welds.
4.0 Reason for Request Enclosure 1 provides a complete listing of the applicable RPV nozzles .
The proposed alternative provides an acceptable level of quality and safety, and the reduction in scope could provide a dose savings of as much as 8.1 Person-Rem for Unit 1 and 9 .4 Person-Rem for Unit 2, over the remainder of the interval .
Attachment Relief Request Number 14R-17 5.0 Pursuant to 10 CFR 50.55a(a)(3)(i), relief is requested from performing the required 100% of the RPV nozzle assemblies at QCNPS Unit 1 and Unit 2 identified n Tables 5-1 and 5-2 below, (i.e ., and delineated in Enclosure 1) . As an Verna Ids and inner radii identified in Tables 5-1 and 5-2, EGC proposes of 25% of the nozzle-to-vessel welds and inner radius sections, includ one nozzle from each system and nominal pipe size, in accordance with Code Case N-702 . For the applicable nozzle assemblies identified in Enclosure 1, this would mean one ' from each of the groups identified below:
Table 5-1 Unit 1 Summary Group Total Number Minimum Number to be ~ Comments Examin ed Recirculation 10 Five completed . Four in 2005 Inlet (N2) during Q1 R18. One in 2007 during Q1 R19.
Main Steam (N3) 4 Four completed. Two in 2005 during Q1R18. Two in2007 during Q1 R19 .
Core Spray (N5) 2 Two completed. One in 2005 during Q1 R18 and one in 2007 during Q1R19.
Nozzles on 3 Three19completed
. during 2007 in Vessel Top Q1R Head (116, N7)
Jet Pump 2 One completed during 2005 in Instrumentation Q1R18-(N8)
Attachment Relief Request Number 14R-17 Table 02 Group Total Number Minimum Number to be Comments Examined Recirculation 10 3 Five completed. Two in 2004 Inlet (N2) during 02817. Three in 2006 during 028 18 Main Steam (N3) 4 1 Two completed in 2008 during 02819.
Core Spray (N5) 2 1 Two completed in 2008 during 0281 9.
Nozzles on 3 1 Three completed in 2008 during Vessel Top (UR19.
Head N6, N7 Jet Pump 2 1 One completed in 2008 during Instrumentation 02819.
(N8)
Code Case N-702 stipulates that a VT-1 examination may be used in lieu of the volumetric examination for the inner radii (i.e., Item No. B3 .100) . EGC is not currently using Code Case N-648-1 at QCNPS for the identified components on enhanced magnification visual examination, and has no plans of using Code Case N-648-1 in the future . Volumetric examinations of all inner radii will be completed .
Electric Power Research Institute (EPRI) Technical Report 1003557, "BWRVIP-108:
BWR Vessel and Internals Project Technical Basis for the Reduction of Inspection Requirements for the Boiling Water Reactor Nozzle-to-Vessel Shell Welds and Nozzle Blend Radii," provides the basis for Code Case N-702. The evaluation found that failure probabilities at the nozzle blend radius region and nozzle-to-vessel shell weld due to a low temperature overpressure event are very low (i.e., <1 x 10-6 for 40 years) with or without inservice inspection . The report concludes that inspection of 25% of each nozzle type is technically justified.
This EPRI report was approved by the NRC in an SE dated December 19, 2007 (i.e.,
ADAMS Accession No. ML073600374) . Section 5 .0, "Plant-Specific Applicability," of the SE indicates that each licensee who plans to request relief from the ASME Code,Section XI requirements for RPV nozzle-to-vessel shell welds and nozzle inner radius sections may reference the BWRVIP-108 report as the technical basis for the use of ASME Code Case N-702 as an alternative. However, each licensee should demonstrate the plant-specific applicability criteria from the BW RVI P- 108 report to its units in the relief request by showing that all the general and nozzle-specific criteria addressed below are satisfied {i.e., as described in Enclosure 2) .
Attachment Relief Request Number 14R-17 The maximum RPV heatup/cooldown rate is limited to less than 115 OF per hour.
QCNPS Technical Specification (TS) 3.4.9,"RCS Pressure and Temperature (P/T) Limits," provides a limiting condition for operation (LCO) and a corresponding surveillance requirement (SR) that ensure the reactor coolant system heatup and cooldown rates are less than or equal to 100°F/hr . The SR (i .e., monitoring of reactor vessel heatup and cooldown rates) is implemented by QCNPS operations surveillance procedure QCOS 0201-02, "Primary System Boundary Thermal Limitations." This heatup/cooldown rate also described in the QCNPS Updated Final Safety Analysis Report UFSAR) Section 5.3 .2, "Pressure-Temperature Limits," and UFSAR Table 5.1-1, "Reactor Coolant System Data."
(2) For the Recirculation Inlet Nozzles, the following criteria must be met:
- a. (Pr/t)/CRPV<1 .15 ; The calculation for the QCNPS N2 Nozzle results in 1 .065 which is less than 1 .15 b . [p(r.2 +r2)/(r
.2 i2
- r )]/CNOZZLE< 1 . 15 ; The calculation for the QCN PS N2 Nozzle results in 0.972, which is less than 1 .15.
For the Recirculation Outlet Nozzles, the following criteria must be met:
- a. (p r/t)/CRPV< 1 .15; The calculation for the QCNPS N1 Nozzle results in 1 .273 which is higher than 1 .15.
- b. [p(r ) 2 2+r
- 2)/(r2 -ri 2
)1/CN0ZZLE< 1 . 15; The calculation for the QCNPS N1 Nozzle results in 0.840 which is less than 1 .15 .
Based upon the above information, all QCNPS RPV nozzle-to-vessel shell welds and nozzle inner radii sections, with the exception of the Recirculation Outlet Nozzles, meet the criteria and therefore Code Case N-702 is applicable . However, the Recirculation Outlet Nozzles do not meet all of the criteria and Code Case N-702 would not be applied . Additional discussion is provided in Enclosure 2.
Therefore, implementation of Code Case N-702 examination requirements provides an acceptable level of quality and safety pursuant to 10 CFR 50 .55a(a)(3)(i) for all applicable, full penetration RPV nozzle-to-vessel shell welds and nozzle inner radii sections .
6 .0 Duration of Proposed Alternative The proposed alternative will be used for the remainder of the fourth 10-year rval of the QCNPS ISI Program .
7.0 Precedents The NRC has recently approved a similar request for the Duane Arnold Energy Center . This approval is documented in ADAMS Accession Number ML082040046.
Enclosure 1 Relief Request Number 14R-17 Applicable Nozzles Unit 1 App le Nozzles les Component ID Category Item System Nominal Comments Number Number I Pipe Size N2A Nozzle B-D 13190 Recirc Inlet 1 12" PDI Exam 2005 N2A IRS EKED 63100 Recirc Inlet 12" PDI -Exam 2005 N2B Nozzle N2B IRS "M
B-D 83 .90 83 .100 Retire Inlet Recirc Inlet 12" 12" PDI Exam PDI Exam 2005 2005 N2C Nozzle B-D 83 .90 Recirc Inlet 12" PDI Exam 2007 N2C IRS B-D 83 .100 Recirc Inlet 12" PDI Exam 2007 N2D Nozzle B-D 83 .90 Recirc Inlet 12" PDI Exam 2005 N2D IRS B-D 83 .100 Recirc Inlet 12" PDI Exam 2005 WE Nozzle B-D B&90 Recirc Inlet 1 12" PDI Exam 2005 N2E IRS B-D 83 .100 Recirc Inlet 12" PDI Exam 2005 N2F Nozzle B-D 83 .90 Recirc Inlet 12" ~
N2F IRS B-D 131100 Recirc Inlet N2G Nozzle B-D 83 .90 Recirc Inlet N2G IRS B-D 83 .100 Recirc Inlet 12" N2H Nozzle B-D 83 .90 Recirc Inlet N2H IRS B-D 83 .100 Recirc Inlet NO Nozzle B-D 83 .90 Recirc Inlet I N 2J IRS B-D 83 .100 Recirc Inlet N2K Nozzle B-D 83 .90 Recirc, Inlet N2K IRS B-D 83 .100 Recirc Inlet 1 N3A Nozzle B-D 83 .90 Main Steam 20" PDI Exam 2005 N3A IRS B-D 83 .100 Main Steam 20" PDI Exam 2005 N3B Nozzle B-D 83 .90 Main Steam 20" PDI Exam 2005 N3B IRS B-D 83 .100 Main Steam 20" PDI Exam 2005 N3C Nozzle B-D B&90 Main Steam 20" PDI Exam 2007 N3C IRS B-D 83 .100 Main Steam 20" PDI Exam 2007 N3D Nozzle B-D 83 .90 Main Steam 20" PDI Exam 2007 N3D IRS B-D 83 .100 Main Steam 20" PDI Exam 2007 N5A Nozzle B-D 83 .90 Core Spray 101, PDI Exam 2005 N5A IRS B-D 131100 Core Spray 10 .1 PDI Exam 2005 N5B Nozzle ND EMWO Core Spray 10" PDI Exam 2007 N513 IRS B-D 83 .100 Core Spray 10 1, PDI Exam 2007 N6A Nozzle B-D 83 .90 Head Vent 6" PDI Exam 2007 N6A IRS B-D 83 .100 Head Vent 6" PDI Exam 2007 N6B Nozzle B-D 83 .90 Head Vent 6" PDI Exam 2007 N6B IRS B-D 83 .100 Head Vent 6" PDI Exam 2007 N7 Nozzle B-D 83.90 Head Vent 4" PDI Exam 2007 N7 IRS B-D 83 .100 Head Vent 4" PDI Exam 2007 N8A Nozzle B-D 183 .90 Jet Pump 4" PDI Exam 2005 Instrumentation N8A IRS B-D 83 .100 Jet Pump 4" PDI Exam 2005 Instrumentation N813 Nozzle B-D 83 .90 Jet Pump 4" Instrumentation N8B IRS B-D 83 .100 Jet Pump 4" 1 1 Instrumentation ~
Enclosure 1 Relief Request Number 14R-17 Applicable Nozzles Unit 2 Pypl&aWe Nozzles Component ID Category Item System ~ Nominal Comments Number Number Pipe Size N2A Nozzle B-D 83 .90 Recirc Inlet 12" PDl Exam 2004 N2A IRS "E 83 .100 Recirc Inlet 12" PDI Exam 2004 N2B Nozzle B-D 83 .90 Recirc Inlet 12" PDI Exam 2006 N2B IRS B-D 83 .100 Recirc Inlet 12" PDl Exam 2006 N2C Nozzle B-D B3 .90 Recirc Inlet 12" PDI Exam 2004 N2C IRS B-D 83 .100 Recirc Inlet 12" PDI Exam 2004 N2D Nozzle B-D 83 .90 Recirc Inlet -12" PDI Exam 2006 N2D IRS B-D 83 .100 Recirc Inlet 12" PDI Exam 2006 N2E Nozzle B-D 83 .90 Recire Get 1 17 PDl Exam 2006 N2E IRS B-D 83 .100 Recirc Inlet ~ 12" PDI Exam 2006 N2F Nozzle B-D 83 .90 Recirc Inlet --
N21F IRS B-D 83 .100 Recirc Inlet N2G Nozzle OD 83 .90 Recirc Inlet N2G IRS B-5 83 .100 Recirc Inlet N2H Nozzle B-D 83 .90 Recirc Inlet N2H IRS B-D 83 .100 Recirc Inlet N2J Nozzle B-D 83 .90 Recirc Inlet NO IRS B-D 83 .100 Recirc Inlet NOME -
7ffi~
N2K Nozzle B-D 83 .90 Recirc Inlet -
N2K IRS B-D 83 .100 RecircSteam Inlet 52A Nozzle B-D 83 .90 Main 7 N3A IRS B-D 83 .100 Main Steam N3B Nozzle B-D B3 .90 Main Swam PDI Exam 2008 N3B IRS B-D 83 .100 Main Steam PDI Exam 2008 N3C Nozzle B-D B190 Main Steam N3C IRS B-D B3 .100 Main Steam 20.
20--
20" 0"
N3D Nozzle B-D E-3 .90 Main Steam 20" PDI Exam 2008 N3D IRS B-D 131100 Main Steam 20" PDI Exam 2008 N5A Nozzle B-D 83 .90 Core Spray 10 .1 PDI Exam 2008 N5A IRS B-D 83 .100 Core Spray 10 PDI Exam 2008
.1 N513 Nozzle B-D 13190 Core Spray 10 PDI Exam 2008 1,
N5B IRS B-D 83 .100 Core Spray 10 .1 PDI Exam 2008 N6A Nozzle B-D B300 Head Vent 6" PDI Exam 2008 N6A RS OD 83 .100 Head Vent 6- PDI Exam 2008 N6B Nozzle B-D 83 .90 Head Vent 6" PDI Exam 2008 N6B IRS B-D 83 .100 Head Vent 6" PDI Exam 2008 N7 Nozzle B-D 83 .90 Head Vent 4" PDI Exam 2008 N7 IRS B-D 83 .100 Head Vent 4" PDI Exam 2008 N8A Nozzle B-D 83 .90 Jet Pump 4" PDI Exam 2008 Instrumentation N8A IRS B-D 83 .100 Jet Pump 4" PDI Exam 2008 Instrumentation N8B Nozzle B-D 83 .90 Jet Pump 4" Instrumentation N8B IRS B-D 83 .100 Jet Pump 4" 1 Instrumentation 1 1 I I I
st Number 14R-17 Plant Specific Applicability he maximum Reactor Pressure Vessel (RPV) hP,,,itun?(,.nnlcInwn rate is limited fo SPCC than_
-F/hour .
Response : QCNPS Technical Specification (TS) 3.4 .9.RCS Pressure and Temperature (R,7) Limits," provides a limiting condition for operation CO) and a corresponding surveillance requirement (SR) that ensure eactor coolant system heatup and cooldown rates are less than or equal to 100`F ,'hr . The SR (i .e ., monitoring of reactor vessel heatup and Cooldown rates) is implemented by QCNPS operations surveillance procedure QCOS 0201-02 . "Primary System Boundary Thermal Limitations ." This hea1uptcooldown rate is also described in the QCNPS Updated Finai Safely Ariaiysis Report (UFSAR) Section 5.3.2, "Pressure-Temperature limits," and UFSAR Table 5.1-1, "Reactor For Recircula (2) (Pr/t)/CRPV< 1 .15 P-"*,,"RPV Normal Operating Pressure 1005 r:--RPV inner radius 1215 t-*=RPV wall thickness 6.125 CRPV= 1933-2 (Pr/0/CRPV = 1 .065 <1 .15 (3) [p(r. rc4-ri"' )1/CNOZZl_E< 1 .15 P= RPV Normal Operating Pressure 1005 ro=nozzle outer radius 12 .5 ri=nozzle inner radius 5 .941 Awaz 1637
[p(r.2 2)/( 2
+r WCNOZZLE 0.972 <1 .15 For Recirculation Outlet Nozzles (4) (Pr/t)/CRPV< 1 .15 P=RPV Normal Operat 1005 r=RPV Our radius 1215 t=FIP\/ wall thickness &125 CRPV= 16171 (Prtt)/CRPV = 1 .273 >1 .15 (5) Mr.
P= R PV Normal Oper Pressure 1005 ro=no22ie outer radius 26.5 ri =nozzle inner radius 111375 NOZZLE 1977 CNOMME =: 1840 <1 .15